Submission #890711


Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define FORE(i, a) for (auto i = a.begin(); i != a.end(); ++i)
#define REPU(i, a, b) for (int i = (a); i < (b); ++i)
#define REPD(i, a, b) for (int i = (a); i > (b); --i)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())

vector<string> split(const string &s, char c) {
	vector<string> v;
	stringstream ss(s);
	string x;
	while (getline(ss, x, c)) v.push_back(x);
	return v;
}

#define DEBUG(args...) { vector<string> _v = split(#args, ','); err(_v.begin(), args); }

void err(vector<string>::iterator it) {}

template<typename T, typename... Args>
void err(vector<string>::iterator it, T a, Args... args) {
	cerr << "[DEBUG] " << it -> substr((*it)[0] == ' ', it -> length()) << " = " << a << '\n';
	err(++it, args...);
}

typedef long long ll;
const int MOD = 1000000007;

template<class T, class U> inline T tmin(T a, U b) { return (a < b) ? a : b; }
template<class T, class U> inline T tmax(T a, U b) { return (a > b) ? a : b; }
template<class T, class U> inline void amax(T &a, U b) { if (b > a) a = b; }
template<class T, class U> inline void amin(T &a, U b) { if (b < a) a = b; }
template<class T> inline T tabs(T a) { return (a > 0) ? a : -a; }
template<class T> T gcd(T a, T b) { while (b != 0) { T c = a; a = b; b = c % b; } return a; }

int main(int argc, char *argv[]) {
	ios_base::sync_with_stdio(false);

	int n;

	cin >> n;
	vector<int> a(n + 1);
	REPU(i, 1, n + 1) cin >> a[i];
	int ans = 0;
	REPU(i, 1, n + 1) {
		if (a[a[i]] == i) ans++;
	}
	ans /= 2;
	cout << ans << endl;

	return 0;
}

Submission Info

Submission Time
Task B - Friendly Rabbits
User rantd
Language C++14 (GCC 5.4.1)
Score 200
Code Size 1685 Byte
Status AC
Exec Time 11 ms
Memory 640 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 200 / 200
Status
AC × 3
AC × 15
Set Name Test Cases
Sample 0_00.txt, 0_01.txt, 0_02.txt
All 0_00.txt, 0_01.txt, 0_02.txt, 1_00.txt, 1_01.txt, 1_02.txt, 1_03.txt, 1_04.txt, 1_05.txt, 1_06.txt, 1_07.txt, 1_08.txt, 1_09.txt, 1_10.txt, 1_11.txt
Case Name Status Exec Time Memory
0_00.txt AC 3 ms 256 KB
0_01.txt AC 2 ms 256 KB
0_02.txt AC 2 ms 256 KB
1_00.txt AC 2 ms 256 KB
1_01.txt AC 11 ms 640 KB
1_02.txt AC 11 ms 640 KB
1_03.txt AC 11 ms 640 KB
1_04.txt AC 11 ms 640 KB
1_05.txt AC 11 ms 640 KB
1_06.txt AC 11 ms 640 KB
1_07.txt AC 11 ms 640 KB
1_08.txt AC 6 ms 384 KB
1_09.txt AC 10 ms 640 KB
1_10.txt AC 9 ms 512 KB
1_11.txt AC 4 ms 384 KB